1. Field
Embodiments relate to a method of forming a polycrystalline silicon layer and a method of manufacturing a thin film transistor (TFT).
2. Description of the Related Art
Thin film transistors (TFTs) are a particular kind of field effect transistor (FET) manufactured by forming a semiconductor thin film on an insulating support substrate. A TFT may include a gate, a drain, and a source. TFTs may be used in, e.g., sensors, memory devices, and optical devices, and may be used as pixel switching devices or operating devices of flat panel displays.
Commercially available LCD products, e.g., notebook PCs, monitors, TVs, or mobile devices, may include an amorphous-silicon TFT (a-Si TFT).
Amorphous-silicon refers to silicon that has an irregular atomic arrangement, unlike that of a crystal, and may have a short range order, e.g., may not have a long range order. An amorphous-silicon may be easily deposited over a large area and may be easily formed on a glass substrate at low temperatures. Due to these features, amorphous-silicon is frequently used in TFTs. However, in active-matrix organic light emitting diode (AMOLED) products, high-performance devices that have an electron mobility rate, e.g., about 0.5 to about 1 cm2/Vs, higher than that of an a-Si TFT, may be required. Thus, a method of manufacturing the high-performance TFTs is desirable.
A polycrystalline silicon TFT (poly-Si TFT) may exhibit a significantly higher performance, compared to an a-Si TFT. An electron mobility rate of a poly-Si TFT may be in the range of a few to several hundred cm2/Vs; and a poly-Si TFT may facilitate mounting of a data operating circuit or peripheral circuit requiring a high electron mobility rate on a substrate. In addition, a channel of a TFT may be small so as to increase an aperture ratio of a screen. In addition, there may be no limitation on an interconnection pitch for connection to an operating circuit along with an increasing pixel number due to the installation of the operating circuit. Thus, high-resolution may be obtained. Also, operating voltage and electric power consumption may be reduced and device characteristics may be far less degraded.